i dont know about four eye stuff, but have played on the 88. choppiness to me, sounds like the above mentioned rail bushings. on the 88, they are metal with rubber inserts. one on top, one on the bottom. if they are loose and the rail is not greased, there are tight spots of binding and such, and the jumpiness. steel wool and good grease on stuff really helps. with the door panel off, you should be able to run the windows up and down and see where it is binding up while watching for binding or slop (causing binding). i greased the heck out of it all in there. people say dirt will stick to the grease. well, there was no grease in there, stuff was rusty and not flowing smoothly. i would rather have grease with some surface dirt than rusty stuff in there. i clean them up whenever the door panels are off.
BTW, again, i dont know about similarity, but getting to that stuff is tight, but not bad. there are also plastic bushings on the bottom of the window. if they are loose, when the window catches, they allow it to tilt sometimes.
sorry this is so fragged. typed as i thought about it. my two cents worth. good luck to all. my two cents worth.